1. Field of the Invention
The present invention relates to a dot matrix display panel system and, more particularly, to a display control system which displays any desired portion of the image with increased magnification.
2. Description of the Prior Art
In a television video signal display panel or an electronic viewfinder, it is convenient when a desired image portion is displayed with increased magnification. Such a display system generally includes a dot matrix display panel having a plurality of picture elements aligned in a matrix fashion. The resolution, which determines the picture quality of the dot matrix display panel and the size of decipherable characters, depends on the number of the picture elements included in the dot matrix display panel.
When an image signal is constructed to be applied to a matrix display panel having 500 (H).times.240 (V) picture elements, one character is generally displayed by 8 (V).times.6 (H) dots (picture elements). If a small matrix display panel having 250 (H).times.120 (V) picture elements is employed to display the image signal, the scanning lines are thinned so that one character is displayed by 4 (V).times.3 (H) dots (picture elements). In this case some characters become indecipherable. Thus, it is preferable that a desired image portion is displayed with increased magnification so that one character included in the selected image portion is displayed by 8 (V).times.6 (H) dots as if the matrix display panel had 500 (H).times.240 (V) picture elements.
An image enlarging system in an electronic viewfinder having a dot matrix display panel is disclosed in copending U.S. patent application, "ELECTRONIC VIEWFINDER", Ser. No. 530,468, filed on Sept. 8, 1983 by Yasuo Torimaru and Masahiro Yoshimura, now U.S. Pat. No. 4,589,029 and assigned to the same assignee as the present application, wherein the shift signal for shifting the video signal has a pulse width corresponding to the degree of magnification, and synchronizing signals are delayed in accordance with the image portion to be magnified.
The display control system disclosed in the above-mentioned patent is effective to display a desired portion in an enlarged size. However, an external control signal must be applied to X and Y delay circuits to select the portion to be enlarged.